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Oksanka [162]
3 years ago
5

Solve the systems by the addition method x - 2y = - 4 2x + y = 7

Mathematics
1 answer:
vfiekz [6]3 years ago
5 0
<h2>x - 2y = -4</h2><h2>2x + y = 7</h2><h2 />

To solve this system of equations by addition, our first goal is to cancel

out one of the variables by adding the two equations together.

However, if we add these two equations together right away, nothing

will cancel so we need to set things up so a variable will cancel.

Notice that we have an 2x in our second equation.

If we had a -2x in our first equation, then the x's would cancel out.

In order to create a -2x in the first equation, we simply

multiply both sides of the first equation by -2.

So we have (-2)(x - 2y) = (-4)(-2) which can be rewritten as -2x + 4y = 8.

Now rewrite both equations, as shown below.

<h2>-2x + 4y = 8</h2><h2>2x + y = 7</h2><h2 />

Now when we add the equations together, the x terms

will cancel out and we're left with 5y = 15.

Dividing both sides by 5, <em>y = 3</em>.

To solve for x, plug a 3 in for y in either one of our 2 original equations.

So let's go with our second equation.

Plugging a 3 in for y, we get 2x + (3) = 7.

Now subtract 4 from both sides to get 2x = 4.

Dividing both sides by 2, we fid that <em>x = 2</em>.

Since x = 2 and y = 3, our answer is the ordered pair (2, 3).

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Is it possible to build a triangle with inside angles of 90 degrees , 50 degrees, and 60 degrees?
N76 [4]

Answer:

No

Step-by-step explanation:

Given: Angles of a triangle are equal to 90 degrees , 50 degrees, and 60 degrees

To check : if it possible to build a triangle with given angles

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According to angle sum property of a triangle, sum of angles of a triangle is equal to 180^{\circ}

Here,

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7 0
2 years ago
Ashley brought 7/8 gallon of lemonade to the party.
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3 0
3 years ago
Read 2 more answers
We are standing on the top of a 320 foot tall building and launch a small object upward. The object's vertical altitude, measure
STALIN [3.7K]

Answer:

The highest altitude that the object reaches is 576 feet.

Step-by-step explanation:

The maximum altitude reached by the object can be found by using the first and second derivatives of the given function. (First and Second Derivative Tests). Let be h(t) = -16\cdot t^{2} + 128\cdot t + 320, the first and second derivatives are, respectively:

First Derivative

h'(t) = -32\cdot t +128

Second Derivative

h''(t) = -32

Then, the First and Second Derivative Test can be performed as follows. Let equalize the first derivative to zero and solve the resultant expression:

-32\cdot t +128 = 0

t = \frac{128}{32}\,s

t = 4\,s (Critical value)

The second derivative of the second-order polynomial presented above is a constant function and a negative number, which means that critical values leads to an absolute maximum, that is, the highest altitude reached by the object. Then, let is evaluate the function at the critical value:

h(4\,s) = -16\cdot (4\,s)^{2}+128\cdot (4\,s) +320

h(4\,s) = 576\,ft

The highest altitude that the object reaches is 576 feet.

6 0
3 years ago
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